On a warm day, a driver checks the air pressure in a car tyre. At night, the temperature drops and the air pressure in the tyre decreases. There are no air leaks in the tyre. Why does the pressure decrease?
The air molecules in the tyre move more slowly.
The volume of the air in the tyre decreases.
The volume of the air in the tyre increases.
The air molecules in the tyre stop moving.